Reported to engineering.
The only known workaround is to upgrade the target server to OES2018-SP2. The migration can then be started over. It is possible to resume the migration, but the migration tool does require authentication to the source server. This can be done using these steps:
**All these steps are done on the target server**
1) Load the saved migration project and authenticate to the target server
2) Run "yast2 lan" and modify the interface and add the source IP address as an additional address
3) Modify /etc/opt/novell/eDirectory/conf/nds.conf and add source IP to the n4u.server.interfaces line (ie. n4u.server.interfaces=192.168.0.2@524,192.168.0.1@524)
4) Modify /etc/opt/novell/sms/smdrd.conf and replace the "ip:" setting with "ip: <source_ip>" (ie. ip: 192.168.0.1)
5) Restart ndsd and novell-smdrd by running "rcndsd restart" and "rcnovell-smdrd restart"
6) Authenticate to source server in miggui
7) Click the Transfer ID button in miggui
8) Undo the configuration changes made in steps 3 and 4
9) Restart ndsd and novell-smdrd by running "rcndsd restart" and "rcnovell-smdrd restart"
10) Run "yast2 lan" and remove source IP from the interface
11) Continue with the Transfer ID migration